The nation's children's hospitals are lobbying Congress to change a provision in the pending healthcare legislation that industry leaders say will reduce their federal funding by as much as $876 million. Hospital groups in July agreed to a $155 billion reduction in federal payments over 10 years, part of a broader effort to lower medical costs. But those cuts would have a lopsided effect on children's hospitals, the industry's trade group says, and could cause deep reductions in services.